The aim of this research is to extend our understanding of the biochemical basis of inflammation and of the role of complement in certain biological observations. We are approaching this goal by designing peptides which can serve as specific substrates, inhibitors, and affinity ligands for purification of the C3 and C5 convertases, key enzymes in complement-mediated inflammation. Peptides will be synthesized by the Merrifield method of solid-phase synthesis. Substrate activity will be measured by the use of fluorescent, radiolabeled, and chromogenic substrates. Inhibition will be measured by inhibition of cleavage of such substrates, as well as inhibition of complement-mediated hemolysis and of cleavage of radiolabeled C3 and C5. The specificity of such effects for the C3 and C5 convertases will be assessed by comparison with the effects of inhibitors on other enzymes. The request for supplemental funds is primarily due to the need for a better purification method for the synthetic peptides.